The trade comes as somewhat of a shock. The previous front office of the Mariners clearly underappreciated Miller. Miller has been an above-average shortstop, though errors at key times have soured the opinion of Miller for some fans, and his combination of left-handed power and plate discipline is hard to find from a shortstop. This isn’t the first time the Mariners have traded away a reputed power-possessing shortstop to the Rays, and Nick Franklin hasn’t exactly flourished in Tampa Bay, posting a 42 wRC+ in 2015. Miller probably takes over at shortstop right away in Tampa Bay, as the team gave most of their innings last year to Asdrubal Cabrera (infuriatingly, another former Mariner) who is a free agent this offseason.

The Rays took on two reclamations projects in Morrison and Farquhar. Both could reclaim some of the success they were expected to have at different points in their career, but both likely had the trade value you’d expect from players who have performed and roughly replacement level. Morrison made $2.725 million in 2015, and will likely get another raise going into his final year of arbitration before free agency. Farquhar was going into his Age-29 season, and struggled to stay in the big leagues in 2015. The Mariners have Mark Trumbo under contract and may have some interest in giving Jesus Montero a shot at first base. Neither of which figures to be substantially worse than Morrison, and both could easily be better. Farquhar is a reliever, and many good teams have been successful forging productive, or even dominant relievers from the remains of failed starters.

Karns is a pitcher with basically average peripherals, but one who has done it while striking out nearly a batter per inning in his career. He’s entering his Age-28 season, and will be cheap for at least another two years, and is under team control for five more years at least. Karns allows more fly balls than average, and walks more batters than average, which was a limiting factor for him in 2015, his first full year in the majors. He has a fastball that averages about 92 MPH, and he has a knuckle-curve and a change-up, both of which are generally considered about average. Karns will probably spend all of 2015 in the Mariners rotation, and if he can manage his walks he may be able to turn in results that are well above average. The Mariners have a hole in their rotation if they can’t sign Hisashi Iwakuma, and even if they do sign Iwakuma, they’ve got question marks littered throughout the rest of the rotation.

Riefenhauser is unexciting. He’s a lefty reliever who Pitch F/X has averaging less than 90 MPH on his fastball. His swinging strike rate is low, and that is despite throwing more than half sliders. He seems like a guy who was thrown into the deal, perhaps because Jerry DiPoto or one of his staff members has some sort of history scouting Riefenhauser.

The real pivot point for this deal is Boog Powell. The Mariners desperately need a center fielder. While Miller looked like that could be a position for him in the future, it certainly wouldn’t have fulfilled his whole potential, and there could have been limitations in his development as an outfielder. The Mariners are deep at shortstop from an organizational perspective, and Ketel Marte acquitted himself fairly well at the position at the end of 2015. Without a real spot on the field, Miller seemed destined to be unfairly compared to Ben Zobrist for most of the next half-decade. Now he’ll get to go to the land where Zobrist’s emergence occurred. Powell hasn’t been widely regarded as a top prospect. He’s played mostly center field in the minors though, and he’s had mostly good results at the plate. He limits his strikeouts, and has a high walk rate, though his low power may drive his walk rate down if he makes it to the majors. Powell made it to Triple-A in just his Age-22 season, and figures to get a shot in the majors pretty early considering the Mariners lack of depth in the outfield.

This deal isn’t sexy, and by no means did the Mariners fleece the Rays. This is a deal where the Mariners traded an area of strength and depth for an area of weakness, saved some money, and probably made substantial marginal gains. If Karns is the Mariners fifth starter in 2016, that’s great news, because it means the Mariners rotation is pretty good. If he’s their fourth starter, they could still be alright, because Karns is alright. Powell fills an immediate need, and does it with at least reputed defensive prowess, something that has been sorely lacking in Mariners outfields of late. I’m selfishly sad to see Brad Miller go, as he was probably my favorite Mariners on this iteration of the Mariners, if you’ve made it this far in this post I shouldn’t be boring you with my personal feelings.